1. Field of the invention
The present invention relates to a tape structure provided with electronic components, such as resistors, capacitors, etc., each having terminal legs.
2. Description of the Prior Art
For use in the assembly line, the electronic components, such as resistors, capacitors, etc., are aligned in a predetermined pitch and are carried by a tape structure.
As shown in FIG. 1, the tape structure 20 is defined by a base tape 50 and an adhesive tape 60. The base tape 50 has perforations 80 formed along the center thereof with a predetermined pitch. The perforations are used for guiding and advancing the tape structure. Each electric component 10 is defined by a body portion 30 and usually two terminal legs 40a and 40b extending from the body portion 30. The electric components 10 are supported by the tape structure such that terminal legs 40a and 40b are placed across the base tape 50 and are held in place by the adhesive tape 60 applied across terminal legs 40a and 40b over the base tape. When the adhesive tape is applied, corrugations 70a and 70b are formed in the adhesive tape where the terminal legs 40a and 40b exist underneath thereof As indicated in FIG. 1, adhesive tape 60 extends parallel to base tape 50.
Base tape 50 is formed, for example, of a relatively strong and thick paper, such as Kraft paper, whereas adhesive tape 60 is formed, for example, of a thermoplastic with a coating of a thermoplastic adhesive on its one side. One example of the above described tape structure is disclosed in U.S. Pat. No. 4,453,633.
The tape structure as described above is set in an automatic insertion machine (not shown), which cuts the tape structure into segments A0 As shown in FIG. 2, each segment A0 is held between a pallet 12 and a pair of pressing arms 11a and 11b, and is carried to a severing station where the terminal legs are cut to separate the electronic component from the tape structure. The separated electronic component 10 is carried by a holder (not shown) and its terminal legs are inserted into holes of a printed circuit board.
The prior art tape structure has a problem as explained below.
As apparent from FIGS. 1 and 2, recently, from the viewpoint of saving material and reducing the cost, the width of adhesive tape 60 is reduced to narrower than half the width of base tape 50, and also, the terminal legs are shortened so as to extend only halfway across the base tape. The width of the base tape is maintained the same so that the tape structure can be loaded in the conventional automatic insertion machine. When a tape structure with a full size adhesive tape and full length terminal legs is used, such as disclosed in U.S. Pat. No. 4,243,139, each segment A0 can be secured tightly between pallet 12 and pressing arms 11a and 11b, because both pressing arms 11a and 11b are placed between the corrugations. However, when the tape structure shown in FIGS. 1 and 2 is used, only the pressing arm 11b is held between corrugations 70a and 70b. The other pressing arm 11a is placed on a plain face of base tape 50. Accordingly, segment A0 can be easily pivoted, as indicated by an arrow X, about a place under the end of pressing arm 11b, particularly during the carrying or at the severing station. If the terminal legs are severed while the segment is pivoted, the holder may pick up the separated electronic component with the terminal legs directed in the wrong direction. Thus, the electronic component may not be successfully inserted into the printed circuit board.